More and more head mounted devices comprise electronic devices requiring to be powered by a battery.
Such battery requires being charged periodically. Since the weight is an issue for head mounted devices the batteries comprised in such devices cannot be too heavy, thus limiting the capacity of such batteries.
The existing head mounted devices comprise a connector device allowing the user to charge the battery of the head mounted device by connecting the device to a power source.
Wireless charging system exists for smart phones. Such wireless charging system comprises a transmitter connected to a power source that transmits the power to a receiver via an electromagnetic field. For the receiver to efficiently receive the electromagnetic field and convert such electromagnetic field into electrical power it is required that the diameter of the receiver be of at least 30 mm.
Although, such dimension requirement is general acceptable for a smart phone or a connected watch, head mounted device usually do not comprise a 30 mm diameter surface for receiving such wireless power system receiver.
Reducing the dimensions of the wireless power system receiver reduces dramatically the performance of the power system.
Thus there is a need for a head mounted device whose battery can be charged via a wireless power system receiver.
One object of the present invention is to provide such a head mounted device.